Method and apparatus for refrigeration



March 1, 1938. B RANDEL 2,109,502

METHOD AND APPARATUS FOR REFRIGERATION Fil ed Feb. 18, 1936 2Sheets-Sheet l INVENTOR g0 FOLKE RANDEL ATTORNEY 2 Sheets-Sheet 2 B. F.KANDEL METHOD AND APPARATUS FOR REFRIGERATION Filed Fb. 18, 1936ATTORNEY L M m m m .AII a? W w mm a 9 MM 4 3 x, M? F 2 J m March 1,1938.

Patented Mar. 1, 1938 UNITED STATES PATENT OFFICE METHOD AND APPARATUSFOR REFRIGER- ATION Bo Folke Randel, San Diego, Calif.

Application February 18, 1936, Serial No. 64,472

Claims. (01. 62-115) (Granted under the act in March 3, 1883; as amendedApril so, 1928; 370 o. c. 757) This invention relates to refrigerationand is an improvement 'upon the invention disclosed in my companionLetters Patent of the United States cent humidity is utilized tosupplythe necessary energy in much the same manner as this principle isemployed in the wet and dry bulb therof apparatus for practicing theinvention; andv mometer types of hygrometers. This difference intemperature may be augmented by the application of additional heat tothe part in my system corresponding to the dry thermometer and byaccelerating the rate of cooling by'increased evaporation of the part inmy system corresponding to the wet thermometer.

With these and other objects in viewias well as other advantages whichmay be incident to the use of the improvements, the invention con' sistsof the parts and combinations thereof hereinafter set forth and claimed,with the understanding that the several necessary elements constitutingthe same may be varied in proportion and arrangement without departingfrom the nature and scope of the invention, as defined in the'appendedclaims. t

I In order to make the invention more clearly understood, thereare'shown in the accompanying drawings means for carrying the inventioninto practical effect, without limiting the improvements in their usefulapplication to the particular construction, which, for purposes of ex--planation, have been made the subject of illustration.

In the accompanying drawings:

Figs. 1 and 2 are diagrammatic views illustrating the physical theoriesupon which the present invention is based;

Fig. 3 is a diagrammatic view showing one form Fig. 4 illustratesdiagrammatically another embodiment of theginvention. I

Referring to the drawings, and particularly to Figs. 1 and. 2 thereof,let it be assumed that two vessels I and 2, are interconnected by a tube3. Each vessel is partially filled with a liquid such as water. Vessel Iis heated, while 2 is cooled. Under these conditions the pressure in thetwo vessels will be the pressure invessel 2 due to its temperature. Ifvessel 2 is cooled, to say 60 degres F. temperature, the watervaporpressure will be 02562 lbs. absolute in both vessels. In-

- themselves;

crease of temperature outside vessel I will not increase the pressurebut will increase the vaporizing capacity. As long as heat is suppliedto vessel I and removed from vessel 2, the water will boil in I tocondense in vessel 2, both vessels being under the same temperature andpressure.

Referring now to Fig. 2, we have three vessels, 4, 5, and 6interconnected by pipes I and 8. We will assume that vessel 4 contains asubstance which is a liquid at ordinary temperature and capable of beingconverted into a gas at an elevated temperature, and having a low vaporpressure-temperature gradient over the temperature range/of operation.We will assume also, that vessel 6 contains a substance which is aliquid at ordinary temperatures and capable of being converted into agas at an elevated temperature and having a high vaporpressure-temperature gradient over the temperature range of operation.The substances in the vessels 4 and.6 may, for example, be water andhexane, said substances being immiscible withone another when in liquidform and of different specific gravities. Also, they apparatus is anentirely closed and sealed system and the pressure therein is determinedsolely by the vapor pressures of the substances The vessels-4 and 6 andinterconnecting pipes l and 8 may be evacuated by mechanical means or byvaporizing the substances so that their vapors will displace, the air.We will also assume a constant heat supply ,to vessels 4 and 6,.whilevessel '5 is being cooled. Assuming that the temperature is sufiicientto vaporize the substances in vessels 4 and 6 and that the temperatureis low enough to condense the vapors in vessel 5,, then a constant flowof vapors will occur from vessels 4 and 6 into-vessel 5; While the twovapors will diffuse into each other and be present in all the vessels,at least at the start of the process, .we will assume the flow to be ofsuch velocity as to counteract the velocity of diffusion, so that thevapor in vessel 4 with connecting pipe I is water vapor only and vaporin vessel 6 with connecting pipe 8 is hexane vapor only. It is clearthat the total pressure in all the three vessels must be equal. Thusthe. water vapor pressure in vessel 4, which equals the total pressure.willpbethe same as thehexane vapor pressure in vessel 6, and that invessel-5 the vapor pressure will be composed of the partial 5. Ifvessel? is kept at,\say 60 degrees F. temperature, the vapor pressure onthe water in this vessel will be 0.2562 lb. and the vapor pressurehexane vapor in vessel 5, in order to cause conon the hexane will be1.92 lbs, or a total of 2.1762 lbs. The vapor pressurein vessels 4 and 6will now be this total and the temperature required in vessel 4 to boilthe water will be due to this total pressure, which will also be thecase in vessel 6, or approximately 126 degrees in vessel 4 and 65degrees in vessel 6. It is seen that the two liquids will boil orvaporize in their respective vessels, but under considerable differencein temperature. It is also seen that the pressure in vessel 6 is thegreater part of the total pressure.

If the vapor pressure in vessel 6 could be lowered;

the temperature required in vessel 4 could also be lowered to vaporizethe water. This can be done by limiting the inflow of heat to vessel 6while maintaining an unlimited inflow of heat to vessel 4. The liquid invessel 6 will cool by its own vaporization and thus lower its own vaporpressure. Under these conditions it will also be necessary to increasethe partial pressure on the densation and without increasing the totalpressure-in this same vessel. In Fig. 3 an apparatus is illustrated,wherein this is possible.

with reference to this figure, assume a vessel 9 containing water, avassel l0 containing liquid hexane, kerosene or the like and a vessel l2containing a mixture of both water and hexane, or

. kerosene, which due to their different specific weights will cause adivision line I3 with the lighter hexane floating on top of the heavierwater. The vessel 9 is connected with vessel l2 by pipe l5 and in such amanner as to cause the water to pass from vessel I 2 to vessel 9, andvessel I 0 is connected with vessel l2 by pipe M in such a manner as toallow the hexane to'pass from vessel 12 to vessel l0.

Vessels 9 and ID are connected by pipes l6 and I! with a first condenserin the form of a vessel I8 located above the level of the vessels 9, Hand I2 and which connects with the latter through a pipe l9 whichfunctions as a second cpndenser in a manner presently to be described.The vessel 9 is provided with suitable heating means. The vessel I0 isenclosed in an insulated housing ll, preventing heat to reach same fromthe outside, or in'a refrigerator if so desired. The vessel or firstcondenser l8 and the pipe or second condenser'l9 are enclosed in acasing |8a containing a porous material l9a, as unglazed porcelain, andadapted to be saturated-with water or packed in mineral wool or cloth.Air is caused to flow through the casing l8a and porous material [9a byany suitable means to cause the evaporation of the absorbed water andthe resulting cooling of the vessel I 8 and pipe I9. The pipe l9 may belengthened if required by forming same into a coil, helix or other form.The vessel l8 and pipe l9 act as condensers, the cooling being caused bythe evaporation of water from the surrounding material l9a. A fan orblower may be added to cause more rapid-flow of air to cause thisevaporation.

Let it now be assumed that the apparatus is at rest and in equilibriumand that the temperature.

surrounding all parts is degrees F. We will also assume a. relativehumidity of 50 per cent. The equilibrium pressures will be, on hexane3.1 and on the water 0.505 lb. Abs., or, a total of 3.605 lbs. Abs. Bothvapors will be diffused into each other throughout the apparatus. Theliquid level will be at A, B and C in the difl'erent vessels. Actually,the level in vessels l0 and i2 will be higher than in vessel 9, due tothe difierence in specific weights of these media, but this is not shownfor simplicity in presentation.

Water will now be permitted to wet the porous material l9a surroundingthe first and second condensers l8 and I9. These condensers will act asa wet bulb due to the evaporation of the water; and with an 80 degreedry bulb temperature and 50 per cent humidity, the wet bulb temperaturewill be approximately 67 degrees or 13 degrees below the dry bulb. A newpressure equilibruim due to this lower temperature will be establishedwhich, at say 70 degrees, will be as follows: On hexane 2.4 and on water0.3626, or a total of 2.8226 lbs., a drop of 0.83 lb. absolute.

This drop of pressure in the vessel l2, pipe l9 and the vessel or firstcondenser l8 will cause a flow of vapors from vessels I0 and 9m thecondenser. This will also cause evaporation oi liquids in the vessels 9and ID, to supply additional vapors, and this evaporation will beactinually condense to be separated in liquid form in-vessel l2 andreturned to 9 and I0.

The continued removal of heat by the wet bulb condenser, and thecontinued absorption of heat by the hexane liquid in vessel l0 willfinally bring down the temperature in the vessel l0 and the vaporpressure on the hexane to the point at which the wet bulb temperature isinsufiicient to condense same, and this point will'be reached when thetemperature in vessel l0 equals this wet bulb temperature. However,water vapor will continue to flow from vessel 9 to vessel l8 as long asthere is a higher temperature sur rounding the former than surroundingthe. latter. By withdrawing practically all the heat from the'upper partof the condenser I 8, thewater vapor will condense in this vessel toform drops or slugs of liquid which will descend through pipe I9 underthe action of gravity. These slugs will pull uncondensed hexanevapordownwardly in the same manner as condensate return water from a radiatorwill draw uncondensable gases downwardly back to the boiler.

While the pressure is insuflicient in condenser I 8 to condense thehexane vapor, a point will be reached in the descending column wherethis pressure will be sufiicient, provided the pipe 19 is of properlength. The hexane vapor will therefore liquefy and separate itself fromthe water and flow back to the vessel 10. During this action heatisconstantly removed from' the vessel l0 constantly lowering the vaporpressure in this vessel.

While at the start of the operation the two different vapors werediflused into each other all throughout the apparatus, due to the motionof the vapors, the vessel 9 will soon contain only water vapor, and thevessel l0 will contain only hexane vapor. The vapor pressure in vessel 9will also equal the vapor pressure in vessel l0, and the I8 also isunlimited, so that the vapors will conin either vessel l or vessel 9. Ifit is assumed that the temperature in vessel 9 is 76 F. with an outsidetemperature of 80 F. and in vessel l2 1 is 72 F. with an outsidetemperature of 67 F., then the equilibrium will be as follows: Vaporpressure on the water and also on the hexane will be 0.45 lb. absolute.The evaporating temperature of the hexane in the vessel ID will be 14"degrees ,F. Partial vapor pressure on the water in the vessel 18 willbe 0.40 lb. and on hexane vapor 0.05 lb. To liquefy hexane at 72 degreesF. will require a pressure of 2.55 lbs. or a water column approximately5.10 feet, assuming a solid column. With vapor and liquid mixed in thiscolumn to, say per cent each, the height will have to be at least tenfeet.

The pressure in vessel 9 is dependent on the pressure in vessel H1, oron the temperature on hexane liquid. If this temperature rises thepressure in vessel 9 will rise, requiring a higher temperature tovaporize the water. Also, the vapor generated in vessel 9 will cover thesurface as a film, so'that before the temperature in vessel I0 isbrought down sufficiently to bring down the pressure in vessel 9, toenable vaporization by 1 an outside temperature of 80 degrees F., itwill be necessary to supply other heat to vessel 9'. After thetemperature in vessel I0 is down, the ordinary room temperature of 80degrees F. will be sufi'icient to operate the apparatus.

In Fig.4 a modification is shown in which this fact is provided for andthe arrangement so constructed that at no time is any other outsidetemperature required besides the ordinary room temperature, thiseliminating the necessity for additional heat. This particularconstruction embodies a water boiler 30, and a hexane evaporator 3|,connected with a liquid separator 46 by pipes 34 and 35. A wet bulb orfirst condenser 32 is located above the level of the boiler 30 andevaporator 3i and communicates with the separator through a pipe 33which functions as a second condenser and in which the hexane vapor isliquefied as before. In this construction provision is made to permitthe vapor from the hexane evaporator to sweep across the water in theboiler 30 and carry the water vapor commingled therewith through pipe,40 ,to the condenser 32. a

The boiler 30 is provided with a coil 31, one end of which communicatesdirectly with the boiler and the other end of which communicatestherewith through a pipe 38 to assist intransferringthe heat to thewater by causing circulation of this water. A fan or blower 4| is alsoprovided to pass air through a conduit 42 and over the condenser coils32 enclosed in porous material andinsulated by insulation material 45.Water is allowed to drip over the porous material from a suitablesprinkler '43. The saturated air escapes from the condenser through aconduit 44. Provision may be made to allow the'air before it is passedto the condenser to pass over the heating coil 31 and boiler 30 toaccelerate the evaporation at this point.

It will be seen that this arrangement will per- -mit a considerablylower temperature in boiler 30, as the water vapor pressure is now apartial pressure and not a total pressure. Hexane vapor will always bepresent in boiler "30 and diffused with the water vapor therein. Thepartial water pressure will be the same in boiler 30 as in condenser 32,so that as long as the outside temperature surrounding boiler 30 ishigher than the temperature surrounding the condenser 32,

evaporation will occur in the boiler 30 and condensation in condenser32. This action will cause a flow of hexane vapors from evaporator 3|through the pipe 39 to boiler 30, and thence to the first condenser32'where the water apors are liquefied. From the condenser 32 themixture of water of condensation and hexane vapors will be drawndownwardly through the pipe 33, where the latter are condensed. Inotherrespects, the apparatus will operate similarly to the other apparatusdescribed.

Water is mentioned as the motive medium, but other mediums may be used,and the invention includes the use of any and all mediums which may besuitable. Hexane is mentioned as refrigerant, that is to say, normalhexane (hexane boiling at +71 C. at 760 mm.) The term kerosene, asherein used, refers to a mixture of nonane and decane (normal) and ofadensity of approximately .791 to .824. In. the present apparatus normalhydrocarbons from hexane to decane as well as others with likecharacteristics would operate satisfactorily. Other refrigerants may beused and are contemplated in the invention. A wet bulb condenser isdescribed, but other means may be employed to cool the condenser.

Other modifications and changes in the pr'oportions and arrangement ofthe parts may be made by those skilled in the art, without depart ingfrom the nature and scope of the invention as defined in the appendedclaims.

The invention described herein may be manufactured and used by or forthe Government of the United States for governmental purposes withoutthe payment of any royalties thereon or therefor.

I claim: A 1. The method of refrigeration, comprising vaporizing aliquid motive medium; vaporizing a entraining the vaporized refrigerantbetween the descending slugs of liquefied motive medium, thus subjectingthis .vapor to compression suflicient to liquefy the. same in saidsecond condenser, separating the two liquids and returning each to itspoint of vaporization.

2. The method of refrigeration, comprising vaporizing a liquid motivemedium having a predetermined density and a predetermined boiling point;vaporizing a liquid refrigerant having a less density and a lowerboiling point than said,- liquid motive medium; passing the two vaporsto a first condenser, liquefying the vapor of the ing the liquidtodescend by gravity through a second condenser in a series of separatedslugs,

entraining the vaporized refrigerant between the descending slugs ofliquefied motive medium, thus subjecting this vapor to compressionsuflicient to liquefy the same in said second condenser, separating thetwo liquids by the levitation of the liquid refrigerant and returningeach to its point of vaporization.

3. The method of refrigeration, comprising vaporizing a liquid motivemedium consisting of water; vaporizing a liquid, refrigerant consistingof a hydrocarbon of the methane series; passing the two vapors to afirst condenser, liquefying the" vapor of the motive medium in ,saidfirst condenser and allowing the liquid to descend by gravmotive medium.in said first condenser and allowity through a second condenser in aseries of separated slugs, entraining the vaporized refrigerant betweenthe descending slugs of liquefied motive medium thus subjecting thisvapor to 5 compression sufficient to liquefy the same in said secondcondenser, separating the two liquids by the levitation of the liquidrefrigerant and re turning each to its point of evaporation.

4. The method of refrigeration, comprising vaporizing a liquid motivemedium consisting of water; vaporizing a liquid refrigerant consistingof hexane or hexylene; passing the two vapors to a first condenser,liquefying the vapor of the motive medium in said first condenser andallowing the liquid to descend by gravity through a second condenser ina series of separatedslugs, entraining the vaporized refrigerant betweenthe descending slugs of liquefied' motive medium, thus subjecting thisvapor to compression sufficient to liquefy the same insaid secondcondenser, separating the two liquids by the levitation of the liquidrefrigerant and returning each to its point of evaporation.

5. The method of refrigeration, comprising vaporizing a liquid motivemedium consisting of water; vaporizing a liquid refrigerant consistingof kerosene; passing the two vapors to a firstcondenser, liquefying thevapor of the motive medium in said first condenser and allowing theliquid to descend by gravity through a second condenser in a series ofseparated slugs, entraining the vaporized refrigerant between thedescending slugs of liquefied motive medium, thus subjecting this vaporto compression sufiicient to liquefy the same in said second condenser,separating the two liquids by the levitation of the liquid refrigerantand returning each to its pointof vaporization. 6. A refrigeratingapparatus comprising an 40 evaporator for a liquid motive medium; anevaporator for a liquid refrigerant; a receptacle for containing asupply of both liquid motive medium andrefrigerant and in liquidcommunication with each of said evaporators, a condenser located at alevel higher than said evaporators and receptacle and in vaporcommunication with each of said evaporators for liquefying the vaporizedmotive medium; and meanscommunicating with said condenser and saidreceptacle for conducting liquid motive medium liquefied by saidcondenser in a series of separated slugs and vaporized refrigerantentrained between said slugs from said condenser to said receptacleunder the action of gravity, thus to subject said vaporized 55refrigerant to sufficient pressure to liquefy the same during itspassage through said conducting means.

'7. A refrigerating apparatus comprising an evaporator for a liquidmotive medium having a predetermined density and a predetermined boilingpoint; an evaporator for a liquid refrigerant having a less density andlower boiling point than said liquid motive medium; a receptacle forcontaining a supply of both liquid motive medium and refrigerant in'asuperimposed stratum and in liquid communication with each of saidevaporators, a condenser located at a level higher than said evaporatorsand receptacle and in vapor communication with each of said evaporatorsfor liquefying the vaporized motive medium; and means communicating withsaid condenser and said receptacle for conducting liquid motive mediumliquefied by said condenser in a series of separated sings and vaporizedrefrigerant entrained between said slugs from said condenser water andrefrigerant in a superimposed stratum and in liquid communication witheach of said evaporators, a condenser located at a ievel-higner thansaid evaporators and receptacle and in vapor communication with each ofsaid evaporators for condensing the vaporized water; and

means communicating with said condenser and said receptacle forconducting water condensed by said condenser in a series of separatedslugs and vaporized refrigerant entrained between said slugs from saidcondenser tov said receptacle under the action of gravity, thus tosubject said vaporized refrigerant to sufllcient pressure to liquefy thesame during its passage through said conducting means.

9. A refrigerating apparatus comprising an evaporator for water; anevaporator for a liquid refrigerant 'consistingof hexane or hexylene; areceptacle for containing a supply of both water and the refrigerant ina stratum superimposed thereupon and in liquid communication with eachof said evaporators, a condenser located at a level higher than saidevaporators and receptacle and in vapor communication with each of saidevaporators for condensing the vaporized water; and means communicatingwith said condenser and said receptacle for conducting water condensedby said condenser in a series of separated slugs and.vaporizedrefrigerant entrained between said slugs from said condenser to saidreceptacle under the action of gravity, thus to subject said vaporizedrefrigerant to suflicient pressure to liquefy the same during itspassage through said conducting means.

10. A refrigerating apparatus comprising an evaporator for water; anevaporator for a liquid refrigerant consisting of kerosene; a receptaclefoir containing a supply of both water and the refrigerant in astratumsuperimposed thereupon and in liquid communication with each of saidevaporators, a condenser located at a level higher than 'saidevaporators and receptacle and in vapor communication with each of saidevaporators for condensing the vaporized water; and means communicatingwith said condenser and said receptacle for conducting water condensedby said condenser in a series of separated slugs and vaporizedrefrigerant entrained between said slugs from said condenser to saidreceptacle under the action of gravity, thus tosubject said vaporizedrefrigerant to sufiicient pressure to liquefy the same during itspassage through said conducting meansk 11. A refrigerating apparatuscomprising an evaporator for a liquid motive medium; an evaporator for aliquid refrigerant; a receptacle for containing a supply of both liquidmotive medium and refrigerant and in liquid communication with each ofsaid evaporators, a condenser located at a level higher thansaidevaporators and receptacle and in vapor communication with each of saidevaporators for liquefying the vaporized motive medium; and means forconducting increments of said motive medium liquefied by said condenserin a series of separated slugs separated by interposed increments ofsaid vaporized refrigerant from said condenser to said receptaclevaporized refrigerant to suflicient pressure to liquefy the same duringits passage through said conducting means.

12. A refrigerating apparatus comprising an evaporator for a liquidmotivemedium; an evaporator for a liquid refrigerant; a receptacle forcontaining a supply of both liquid motive medium and refrigerant and inliquid communication with each of said evaporators, a condenser locatedat a level higher than said evaporators and receptacle and in vaporcommunication with each of said evaporators for liquefying the vaporizedmotive medium; and a tube for conducting increments of said motivemedium liquefied by said condenser and separated by interposedincrements of said vaporized refrigerant from said condenser to saidreceptacle under the action of gravity, thus to subject said vaporizedrefrigerant to suflicient pressure to liquefy the same during itspassage through said tube.

13. A refrigerating apparatus comprising an evaporator for a liquidmotive medium; an evaporator for a liquid refrigerant; a receptacle forcontaining a supply of both liquid motive medium and refrigerant and inliquid communication with each of said evaporators; a condenser locatedat a level higher than said evaporators and re-' ceptacle and in vaporcommunication with each of said evaporators for liquefying the vaporizedmotive medium; and a bubble column for conducting increments of saidmotive medium liquefied by said condenser and separated by interposedincrements of said vaporized refrigerant from said condenser to saidreceptacle under the action of gravity, thus to subject said vaporizedrefrigerant to sufllcient pressure to liquefy the same during itspassage through said bubble column.

14. A refrigerating apparatus evaporator for a liquid motive medium; anevap .orator for a liquid refrigerant; a receptacle for containing asupply of both liquid motive medium and refrigerant and in liquidcommunication with each of said evaporators, a condenser located at alevel higher than said evaporators and receptacle and in vaporcommunication with each of said evaporators for liquefying the vaporizedmotive medium; and a tube for conducting incrementsof said motive mediumliquefied by said condenser and in capillary contact with the walls ofsaid tube and separated by interposed increments of said vaporizedrefrigerant from said condenser to said receptacle under the action ofgravity, thus to subject said vaporizedrefrigerant to suflicientpressure to liquefy the same during its passage through said tube.

15. A refrigerating apparatus comprising an evaporator for a liquidmotive medium; an evaporator fora liquid refrigerant; a receptacle forcontaining a supply of both liquid motive medium and refrigerant and inliquid communication with each of said evaporators; a condenser located.at a level higher than said evaporators and said receptacl and in vaporcommunication with each comprising an of said evaporators for liquefyingthe vaporized motive medium; and means for conducting increcondenser andincrements of said vaporized refrigerant trapped therebetween, from saidconments of said motive mediumliquefied by said denser to saidreceptacle under the action of gravity, thus to subject said vaporizedrefrigerant to suflicient-pressure to liquefy the same during itspassage through said conducting means.

Bo FOLKE 'RANDEL.

